1. Field of the Invention
The present invention relates to a molding machine for forming molds by making use of molding sand containing a gas hardenable binder, and more particularly, to a molding machine arranged such that binder-containing molding sand is filled in the cavity of a vertical split type molding box under suction and hardened by allowing a hardening gas to flow therethrough under suction.
2. Description of the Prior Art
In a method which has recently been proposed, while air inside the molding box cavity is being extracted so that the pressure therein is reduced, molding sand containing a gas hardenable binder is sucked into the cavity so as to fill up the same and moreover, under suction a hardening gas is allowed to flow through the molding sand so as to harden the same, thereby to form a mold.
It is known that the above-mentioned molding method is much suitable for, e.g., manufacture of cores using a vertical split type molding box. This is because suction applied to the vertical split type molding box allows the box to be firmly clamped by means of the peripheral atmospheric pressure, so that it does not need any strong clamping device.
However, any molding machine which massproduces molds by employing the above-mentioned molding method has not been proposed yet, and there has been a great demand for development of such a molding machine.